ErrLookup › GoogleChrome/lighthouse
GoogleChrome/lighthouse
Automated auditing, performance metrics, and best practices for the web. · JavaScript · 510 source files
Analyzed at 9515cd4e58 on 2026-08-13. 143 documented errors.
| Code / Message | Type | Severity | Tags |
|---|---|---|---|
| Invalid precomputed lantern data file | validation | error | cli, config, lantern, json, performance |
| Please provide a url | validation | error | cli, validation, usage |
| Invalid value: Argument must be a string or a boolean | validation | error | cli, validation, yargs |
| Invalid values. Argument 'output' must be an array from choi | validation | error | cli, validation, output |
| "${str}" is not a valid 'output' value. Argument 'output' mu | validation | error | cli, validation, output |
| --output-path (${value}) cannot be written to | validation | error | cli, validation, filesystem, output |
| Invalid value: Argument 'locale' must be a string | validation | error | cli, validation, i18n |
| Invalid value: Argument 'extra-headers' must be a string | validation | error | cli, validation, network, headers |
| Invalid value: Argument 'throttling' must be an object, spec | validation | error | cli, validation, throttling, performance |
| Invalid value: 'throttling.${key}' must be a number | validation | error | cli, validation, throttling, performance |
| Invalid value: Argument 'screenEmulation' must be an object, | validation | error | cli, validation, emulation |
| Invalid value: 'screenEmulation.${key}' must be a number | validation | error | cli, validation, emulation |
| Invalid value: 'screenEmulation.${key}' must be a boolean | validation | error | cli, validation, emulation |
| Unrecognized screenEmulation option: ${key} | validation | error | cli, validation, emulation, unreachable, internal |
| Launching Chrome on Mac Silicon (arm64) from an x64 Node ins | exception | error | platform, macos, arm64, environment, chrome |
NO_SCREENSHOTS Chrome didn't collect any screenshots during the page load. Please make sure the | exception | error | runtime, chrome, screenshots, trace, headless |
INVALID_SPEEDLINE Chrome didn't collect any screenshots during the page load. Please make sure the | exception | error | runtime, chrome, performance, trace, speedline, headless |
| Unknown directive | validation | warning | seo, robots-txt, validation |
| Invalid sitemap URL | validation | warning | seo, robots-txt, validation, url |
| Invalid sitemap URL protocol | validation | warning | seo, robots-txt, validation, url, protocol |
| No user-agent specified | validation | warning | robots-txt, seo, validation, parsing |
| Pattern should either be empty, start with "/" or "*" | validation | warning | robots-txt, seo, validation, parsing |
| "$" should only be used at the end of the pattern | validation | warning | robots-txt, seo, validation, parsing |
| Syntax not understood | validation | warning | robots-txt, seo, validation, parsing |
NO_LCP The page did not display content that qualifies as a Largest Contentful Paint (L | exception | error | lcp, trace, performance, metrics |
NO_TTI_NETWORK_IDLE_PERIOD Your page took too long to load. Please follow the opportunities in the report t | exception | error | tti, network, performance, metrics |
NO_TTI_CPU_IDLE_PERIOD Your page took too long to load. Please follow the opportunities in the report t | exception | error | tti, cpu, performance, metrics, javascript |
NO_DCL Something went wrong with recording the trace over your page load. Please run Li | exception | error | tti, trace, navigation, performance, metrics |
| FCP All Frames not implemented in lantern | exception | error | fcp, lantern, throttling, metrics, not-implemented |
| LCP All Frames not implemented in lantern | exception | error | lcp, lantern, throttling, metrics, not-implemented |
NO_LCP_ALL_FRAMES The page did not display content that qualifies as a Largest Contentful Paint (L | exception | error | lcp, trace, performance, metrics, all-frames |
NO_LCP The page did not display content that qualifies as a Largest Contentful Paint (L | exception | error | lcp, trace, performance, metrics |
NO_LCP The page did not display content that qualifies as a Largest Contentful Paint (L | exception | error | lcp, trace, performance, metrics, breakdown |
UNSUPPORTED_OLD_CHROME This version of Chrome is too old to support '{featureName}'. Use a newer versio | exception | error | responsiveness, inp, chrome-version, compatibility, trace |
| Responsiveness currently unsupported by simulated throttling | exception | error | responsiveness, inp, throttling, not-implemented, metrics |
NO_SCREENSHOTS Chrome didn't collect any screenshots during the page load. Please make sure the | exception | error | speedline, screenshots, trace, performance, metrics |
NO_SPEEDLINE_FRAMES Chrome didn't collect any screenshots during the page load. Please make sure the | exception | error | speedline, screenshots, trace, performance, metrics |
SPEEDINDEX_OF_ZERO Chrome didn't collect any screenshots during the page load. Please make sure the | exception | error | speedline, speed-index, trace, performance, metrics |
| Expected array but got ${typeof base} | exception | error | |
| Expected object but got ${typeof base} | exception | error | |
| Expected object but got Array | exception | error | |
| Invalid Gatherer type | validation | error | |
| Invalid Audit type | validation | error | |
| module '${requirePath}' has too many possible exports | validation | error | |
| module '${requirePath}' missing default export | validation | error | |
| Invalid expanded Gatherer: | validation | error | |
| Unable to locate `${moduleIdentifier}`. Tried to resolv | validation | error | |
| Unable to locate `${moduleIdentifier}`. Tried to resolv | validation | error | |
| ${pluginName} has unrecognized ${objectName}properties: [${k | validation | error | |
| ${pluginName} has an invalid audits array. | validation | error | |
| ${pluginName} has a missing audit path. | validation | error | |
| ${pluginName} has no valid auditsRefs. | validation | error | |
| ${pluginName} has an invalid auditRef id. | validation | error | |
| ${pluginName} has an invalid auditRef weight. | validation | error | |
| ${pluginName} has an invalid auditRef group. | validation | error | |
| ${pluginName} has no valid category. | validation | error | |
| ${pluginName} has an invalid category tile. | validation | error | |
| ${pluginName} has an invalid category description. | validation | error | config, lighthouse, plugin, validation, i18n |
| ${pluginName} has an invalid category manualDescription. | validation | error | config, lighthouse, plugin, validation, i18n |
| ${pluginName} supportedModes must be an array, valid array v | validation | error | config, lighthouse, plugin, validation, gather-mode |
| ${pluginName} groups json is not defined as an object. | validation | error | config, lighthouse, plugin, validation, groups |
| ${pluginName} has a group not defined as an object. | validation | error | config, lighthouse, plugin, validation, groups |
| ${pluginName} has an invalid group title. | validation | error | config, lighthouse, plugin, validation, groups, i18n |
| ${pluginName} has an invalid group description. | validation | error | config, lighthouse, plugin, validation, groups, i18n |
| ${pluginName} is not defined as an object. | validation | error | config, lighthouse, plugin, validation |
| configPath must be an absolute path | validation | error | config, lighthouse, filesystem, paths |
| `lighthouse:default` is the only valid extension method. | validation | error | config, lighthouse, validation, extends |
| unrecognized category in 'onlyCategories': ${unknown.join(', | validation | error | config, lighthouse, filters, validation, categories |
| onlyAudits cannot be an empty array. | validation | error | config, lighthouse, filters, validation, audits |
| onlyCategories cannot be an empty array. | validation | error | config, lighthouse, filters, validation, categories |
| plugin name '${pluginName}' does not start with 'lighthouse- | validation | error | config, lighthouse, plugin, validation, naming |
| plugin name '${pluginName}' not allowed because it is the id | validation | error | config, lighthouse, plugin, validation, categories |
| Gatherer for ${artifactDefn.id} did not provide a meta objec | exception | error | config, lighthouse, gatherer, validation, artifact |
| Gatherer for ${artifactDefn.id} did not support any gather m | exception | error | config, lighthouse, gatherer, validation, gather-mode |
| Gatherer for ${artifactDefn.id} did not define a "getArtifac | exception | error | config, lighthouse, gatherer, validation, artifact |
| ${auditName} has no audit() method. | exception | error | config, lighthouse, audit, validation |
| ${auditName} has no meta.id property, or the property is not | exception | error | config, lighthouse, audit, validation |
CHROME_INTERSTITIAL_ERROR Chrome prevented page load with an interstitial. Make sure you are testing the c | error_code | error | |
PAGE_HUNG Lighthouse was unable to reliably load the URL you requested because the page st | error_code | error | |
NOT_HTML The page provided is not HTML (served as MIME type {mimeType}). | error_code | error | |
TRACING_ALREADY_STARTED An internal Chrome error occurred. Please restart Chrome and try re-running Ligh | error_code | error | |
PARSING_PROBLEM An internal Chrome error occurred. Please restart Chrome and try re-running Ligh | error_code | error | |
READ_FAILED An internal Chrome error occurred. Please restart Chrome and try re-running Ligh | error_code | error | |
INVALID_URL The URL you have provided appears to be invalid. | error_code | error | |
PROTOCOL_TIMEOUT Waiting for DevTools protocol response has exceeded the allotted time. (Method: | error_code | error | |
DNS_FAILURE DNS servers could not resolve the provided domain. | error_code | error | |
CRI_TIMEOUT Timeout waiting for initial Debugger Protocol connection. | error_code | error | |
MISSING_REQUIRED_ARTIFACT Required {artifactName} gatherer did not run. | error_code | error | |
ERRORED_REQUIRED_ARTIFACT Required {artifactName} gatherer encountered an error: {errorMessage} | error_code | error | |
TARGET_CRASHED Browser tab has unexpectedly crashed. | error_code | error | |
INVALID_URL The URL you have provided appears to be invalid. | exception | error | |
MISSING_REQUIRED_ARTIFACT Required {artifactName} gatherer did not run. | exception | error | |
| No directory provided\nUsage: $0 <lhr directory> <audit id> | validation | error | |
| No audit provided\nUsage: $0 <lhr directory> <audit id> | validation | error | |
| Unexpected file "${run.name}" encountered | validation | error | |
| Can only load ctc files | validation | error | |
| Unexpected tagName "@${tag.tagName.text}" | validation | error | |
| unsupported JSDoc comment: ${JSON.stringify(comment)} | validation | error | i18n, jsdoc, typescript-compat, collect-strings |
| Incorrectly formatted @example: "${rawExample}" | validation | error | i18n, jsdoc, example-tag, collect-strings, validation |
| [${err.message}] Did not find the expected syntax in message | validation | error | i18n, icu, syntax-error, collect-strings, message-format |
| Content cannot appear outside plural or select ICU messages. | validation | error | i18n, icu, plural, select, collect-strings, message-format |
| must use same format and formatType for a given name. Invali | validation | error | i18n, icu, placeholder, format, collect-strings |
| Ctc messages cannot contain double dollar: ${icu.message} | validation | error | i18n, ctc, placeholder, collect-strings, internal-format |
| UIStrings exported but no definition found: ${relativeToRoot | validation | error | i18n, uistrings, export, collect-strings, regex |
| UIStrings defined in file but not exported | validation | error | i18n, uistrings, export, collect-strings |
| string collision: `message` and `description` are the same b | validation | error | i18n, collision, placeholder, deduplication, collect-strings |
| expected locale file to exist: ${traceEnginePath} | validation | error | i18n, locale, trace-engine, dependency, filesystem |
| Invalid API response: ${await response.text()} | exception | error | github-api, network, rate-limit, auth, download-issues |
| Usage $0 <computed file> | validation | error | lantern, baseline, filesystem, cli-usage, assertion |
| missing metric ${metricName} | validation | error | lantern, baseline, metrics, assertion |
| error fetching ${url}: ${response.status} ${response.statusT | exception | error | network, wpt, fetch, lantern, http |
| missing WPT_KEY | validation | error | wpt, env, api-key, config, lantern |
| unexpected status code ${wptResponse.statusCode} ${wptRespon | exception | error | wpt, api, quota, config, lantern |
| unexpected response: ${response.statusCode} ${response.statu | exception | error | wpt, polling, api, lantern, state-machine |
| runtime error: ${lhr.runtimeError} | exception | error | lighthouse, runtime-error, wpt, lantern, retriable |
| run failed to get metrics | exception | error | lantern, metrics, lighthouse-result, data-collection |
| No lantern metrics available, did you run run-on-all-assets. | validation | error | lantern, data-pipeline, baseline, ordering |
| No metrics for ${metric} ${lanternMetric} ${lanternOrBaselin | validation | error | lantern, metrics, evaluation, validation |
| Usage $0: <url> | validation | error | cli, usage, lantern, arguments |
| Could not find with site URL ${INPUT_URL} | validation | error | cli, lantern, site-index, url-mismatch |
| Usage $0 <computed summary file> | validation | error | cli, usage, lantern, file-not-found, ordering |
| Usage $0 <expectations file> | validation | error | cli, usage, lantern, file-not-found, working-directory |
| Timespan already in progress | exception | error | user-flow, state-machine, timespan, navigation |
| Navigation already in progress | exception | error | user-flow, state-machine, navigation |
| No navigation in progress | exception | error | user-flow, state-machine, navigation, ordering |
| No timespan in progress | exception | error | user-flow, state-machine, timespan, ordering |
| Unsupported gather mode | exception | error | user-flow, gather-mode, internal-invariant |
| Need at least one step before getting the result | exception | error | user-flow, result-generation, validation |
| Step "${name}" did not return a result | exception | error | user-flow, audit, runner, internal-error |
| CSV output is not support for user flows | exception | error | csv, user-flows, report-generator, output-mode |
| Invalid output mode: ${outputMode} | exception | error | report-generator, output-mode, validation |
| no script treemap data found | exception | error | treemap, audit, open-tab, validation |
| `getStandaloneReportHTML` is not set | exception | error | report-ui-features, configuration, options, renderer |
| Unsupported locale '${locale}' | exception | error | localization, locale, i18n, format |
| Unsupported locale '${requestedLocale}' | exception | error | localization, locale, swap-locale, i18n |
| provided json is not a Lighthouse result | exception | error | treemap, validation, lhr, json |
| provided Lighthouse result is missing audit: `script-treemap | exception | error | treemap, audit, validation, lhr |
| Save already in progress | exception | warning | github-api, gist, concurrency, reentrancy |
| Error: ${JSON.stringify(json)} | exception | error | github-api, gist, network, rate-limit |
| ${resp.status} fetching gist | exception | error | github-api, gist, network, rate-limit, http-status |
| Failed to find a Lighthouse report (*${GithubApi.LH_JSON_EXT | exception | error | github-api, gist, validation, file-format |
| JSON file was not generated by Lighthouse | exception | error | viewer, validation, lhr, json |
| could not fetch data for locale: ${locale} | exception | error | localization, locale, viewer, network, i18n |